how much for this assignment?

1)
Classical Approach:
Here, we know the outcome of experiment in advance and each outcome is equally probable.
For example when we toss a coin, we know that either head or tail will come and also probability of both head and tail is 1/2.
Relative Frequency Approach:
Here, Probabilities are assigned on the basis of experimentation or historical data.
For example Let we roll the die 50 times and suppose the number of times the outcome 3 is observed
is 10. Thus, Probability of coming 3 is 10/50=0.20
Subjective Approach:
Here, Probabilities are assigned on the basis previous experience, belief, and even feeling.
For example, the probability of a particular share to goes up.
b)
Let A and B are events such that
A: Job security was the important issue
B: salary increment was an important issue.
From given data,
P(A)=0.74
P(B)=0.65
P(A|B)=0.60
i) Here, we have to find P(A and B)
P(A and B)=P(A|B)*P(B)=0.60*0.65=0.39 or 39%
ii) Here, we have to find P(A or B)
P(A or B)=P(A)+P(B)-P(A and B)=0.74+0.65-0.39=1 or 100%
....................................
2)
Here, mean=10 and sd=3
a) P(x>12)=1-P(x<12)

=1-0.7486    using z table for z=0.67
= 0.2514
b) Here, we have to find P(x>275/25)=P(x>11)
=1-P(x<11)

=1-0.6293 using z table for z=0.33
=0.3707     
..............................................
3)
a)
The following null and alternative hypotheses need to be tested:
Ho: μ=0
Ha: μ<0
b)
This corresponds to a left-tailed test, for which we will use z-test for one mean. Because we are given population standard deviation.
c)
The z-statistic is

The p-value is p=0.0446 From z table for z=-1.70
d)
Since p=0.0446<<0.10, it is concluded that the null hypothesis is rejected.
e)
Therefore, there is enough evidence to claim that the new safety equipment is effective.
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